1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 import com.android.dx.gen.BinaryOp; 18 import com.android.dx.gen.Code; 19 import com.android.dx.gen.DexGenerator; 20 import com.android.dx.gen.FieldId; 21 import com.android.dx.gen.Local; 22 import com.android.dx.gen.MethodId; 23 import com.android.dx.gen.Type; 24 import com.android.dx.rop.code.AccessFlags; 25 import java.io.PrintStream; 26 27 public class HelloWorldMaker { 28 private static final Type<PrintStream> PRINT_STREAM = Type.get(PrintStream.class); 29 private static final FieldId<System, PrintStream> SYSTEM_OUT 30 = Type.get(System.class).getField(PRINT_STREAM, "out"); 31 private static final MethodId<Integer, String> TO_HEX_STRING 32 = Type.get(Integer.class).getMethod(Type.STRING, "toHexString", Type.INT); 33 private static final MethodId<PrintStream, Void> PRINTLN 34 = PRINT_STREAM.getMethod(Type.VOID, "println", Type.STRING); 35 36 public static void main(String[] args) throws Exception { 37 38 /* 39 * This code generates Dalvik bytecode equivalent to the following 40 * program. 41 * 42 * public class HelloWorld { 43 * public static void hello() { 44 * int a = 0xabcd; 45 * int b = 0xaaaa; 46 * int c = a - b; 47 * String s = Integer.toHexString(c); 48 * System.out.println(s); 49 * } 50 * } 51 */ 52 53 DexGenerator generator = new DexGenerator(); 54 55 // lookup the symbols of interest 56 Type<?> helloWorld = Type.get("LHelloWorld;"); 57 MethodId hello = helloWorld.getMethod(Type.VOID, "hello"); 58 59 // create some registers 60 // (I'd like a better syntax for this) 61 Code code = generator.declare(hello, AccessFlags.ACC_STATIC | AccessFlags.ACC_PUBLIC); 62 Local<Integer> a = code.newLocal(Type.INT); 63 Local<Integer> b = code.newLocal(Type.INT); 64 Local<Integer> c = code.newLocal(Type.INT); 65 Local<String> s = code.newLocal(Type.STRING); 66 Local<PrintStream> localSystemOut = code.newLocal(PRINT_STREAM); 67 68 // specify the code instruction-by-instruction (approximately) 69 code.loadConstant(a, 0xabcd); 70 code.loadConstant(b, 0xaaaa); 71 code.op(BinaryOp.SUBTRACT, c, a, b); 72 code.invokeStatic(TO_HEX_STRING, s, c); 73 code.sget(SYSTEM_OUT, localSystemOut); 74 code.invokeVirtual(PRINTLN, null, localSystemOut, s); 75 code.returnVoid(); 76 77 // TODO: create the constructor 78 79 generator.declare(helloWorld, "Generated.java", AccessFlags.ACC_PUBLIC, Type.OBJECT); 80 81 // load the dex 82 ClassLoader loader = generator.load(HelloWorldMaker.class.getClassLoader()); 83 Class<?> helloWorldClass = loader.loadClass("HelloWorld"); 84 helloWorldClass.getMethod("hello").invoke(null); 85 } 86 } 87
